Verity is needs to installed in 8.50 and HCM 9.1 version. It no long comes as product withpeoplesoft installation.following link has the details to install the verity search engine.

People HR application has evolved with each version and there was major change in the Personal model. Most of us know what are the major changes in personal model. Some time finding all the detail changes and to understand and back data from old versions during upgrade and re-implementation is a challenge.

We do have details in the people books, It has not evolved as much as application find things on people books is not that friendly. I found one of link hosting the details of the changes hope this will be useful for you as well.